The present invention relates to microscopes, and more particularly to metallographic microscopes.
Three known techniques for characterizing conductor drawing dies are as follows:
One is to introduce, by hand, a piece of conductor to be drawn, through the die, and then pull the conductor either manually or mechanically from the other side of the die. The diameter of the wire conductor is then measured with calibrating tools, thus determining the diameter of the die bearing. By repeating the measurements at different points along the wire, the oval shape of the wire and thus the oval shape of the die bearing may be determined.
Another known technique involves the use of molding pastes which is useful only when one tries to determine the length of the bearing and the working angle of the die, if the diameter of the bearing is above 300 microns. This means that this technique cannot be applied to smaller diameters; and also has the drawback that the measuring is done by means of a comparative reading in which the operators judgment has an influence.
Another conventional technique involves the use of a mechanical measuring device to determine the internal profile of the die. This is accomplished by introducing a needle, which tracks the shape of the internal profile which shape is then shown in a display. However, this technique is useful only when applied to diameters of more than 700 microns. It also has the drawback that the results are interpreted by the operator.